Typically, an electrical cord or conduit is coupled within an electrical connector by a movable conduit jaw. An example of such a jaw is disclosed in Gartland U.S. Pat. No. 3,784,961, the disclosure of which is hereby incorporated herein by reference.
Such jaws are able to grip and secure only one general size of conduit. However, various sizes of conduit are used for different applications.
The conventional means for accommodating a wide range of conduit diameters has been to use a removable or expendable conduit clamp, i.e., one that is used only when smaller diameter cable is used and removed when larger diameter cable is used. The clamp reduces the opening size of the electrical connector, thereby allowing the conduit clamp to effectively grip the smaller diameter cable within the opening.
Such removable clamps have several disadvantages. The electrical connectors leave the factory with the clamps installed and ready to receive smaller diameter conduit. Thus, if the user forgets to remove the clamp or does not realize removal is necessary and attempts to use larger diameter conduit, the conduit may be damaged. Furthermore, removable clamps are easily lost.
Alternatively, permanent clamps have been used, but they require both rotary and translational movement to be effective.
Examples of some prior clamps are disclosed in the following U.S. Pat. Nos. 2,577,748 to Gillespie; 2,911,616 to Townsend; 3,402,382 to DeLar; 3,437,980 to Smith; 3,865,461 to Ludwig; 4,080,036 to Hagel; 4,178,056 to Lee; 4,213,667 to Wittes; and 5,021,006 to Fargeaud et al.
Thus, a need exists to provide an improved electrical wiring device with a clamp capable of gripping various sizes of electrical conduit. This invention addresses this need in the art, along with other needs which will become apparent to those skilled in the art once given this disclosure.